None
N/A
N/A
1. Field of the invention
This invention relates to a method and apparatus for broadcasting of instrumental music, vocal music, and speech using digital techniques. The data is structured in a manner similar to the current standards for MIDI (Musical Instrument Digital Interface) data. The MIDI data is broadcasted to receivers which contain internal sound generators or an interface to external sound generators that create sounds in response to the MIDI data.
2. Description of Related Art
Current broadcast techniques for radio and television utilize both analog and digital techniques for audio program broadcasting. For NTSC television, a subcarrier which is FM modulated provides the sound conveyance. For conventional radio broadcasting, either AM or FM modulation of a carrier is utilized to convey the audio program. For satellite broadcast systems, digital modulations, such as QPSK, are used.
To a greater or lesser degree, these various media all share several limitations inherent in audio program broadcasting. First, their broadcast signals are subject to noise interference, and multipath fading. Second, the bandwidth of the audio program may be severely restricted by regulation, as in the case of AM radio. Third, for low frequency AM radio stations, with restricted antenna heights, the bandwidth of the RF carrier with program modulation will be severely restricted by a high-Q, narrow bandwidth transmitting antenna. Fourth, where high data rate digital broadcasts are used for either television or radio broadcasting, the data will be very vulnerable to error by multipath corruption.
Because of these limitations, the various broadcast systems normally restrict their transmission to a single audio program in order to reduce their bandwidth and improve the received signal to noise ratio. For this reason broadcasters are generally restricted to broadcasting only one specific language and must therefore limit the listening audience to which they appeal in multi-cultural urban areas.
This invention will overcome the above limitations and problems by providing multiple audio data signals for several languages on a conventional radio and television carrier through the use of low bandwidth MIDI data. The term MIDI data used in this invention refers to a variation of standard MIDI data format that, in addition to providing conventional instrumental and other commands, also includes one or more of the following: vocal commands, error detection data, error correction data, and time-tag data. Although this invention is described by using the current standard MIDI data format as a convenient basis, other data formats may be used provided they convey the same types of data information for the control and operation of sound generators at receivers.
Use of MIDI data enables the data rates to be greatly reduced and thus permits the inclusion of large quantities of error correction data. This feature will help overcome random and burst errors in the data transmission. Other novel data processing features are also included in the receiver processor to mitigate any data errors which remain uncorrected by the error correction process.
Furthermore, standard MIDI data also does not currently provide for generation of vocal sounds, except for vocal xe2x80x9cOhhxe2x80x9d and xe2x80x9cAhhxe2x80x9d. As such, it is not capable of encoding the lyrics of a song or encoding speech. This invention solves this problem too, by providing for the transmission of vocal music and speech data for control of a voice synthesizer at the receiver. It is an object of this invention that the data encode for elemental speech sounds.
It is an object of this invention to broadcast MIDI data over FM and AM radio frequencies and over VHF and UHF television frequencies, as well as other electromagnetic frequencies.
It is an object of this invention to have the MIDI data rates very low, thereby making the broadcast signals relatively immune to multipath corruption.
It is an object of this invention to have a method of broadcasting one or several audio programs, in one or more languages, using data which controls and operates a sound generator within, or connected to, a receiver. It is also an object of the invention that the broadcast signal contains data commands which control and operate a sound generator which itself creates the music, lyrics, and speech rather than the signal which is broadcast actually conveying the audio signal waveforms.
It is an object of this invention of having a method of transmitting data that is divided into accumulator periods, of identifying within each accumulator period that each datum occurs, labeling each datum to indicate the time within the accumulator period that each datum occurs, and transmitting the data to a remote receiver. It is further an object of this invention that the data can encode for multiple languages. It is further an object of this invention that the data can encode for multiple programs. It is further an object of this invention that the accumulator periods be grouped into data paths, or data streams. It is further an object of this invention that the accumulator periods are labeled to indicate in which data path the accumulator periods belong.
It is also an object of the invention that for a given vocalist MIDI data for vocal xe2x80x9cnote-offxe2x80x9d commands which are immediately followed by a vocal xe2x80x9cnote-onxe2x80x9d command are deleted by the transmitter prior to transmission. It is also an object of this invention that error detection and correction data are encoded along with the MIDI data and is broadcast from the transmitter to allow for detection and correction of corrupted MIDI data.
It is also an object of this invention that a transmitter processor receives the MIDI data from a data source and divides the MIDI data into accumulator periods, adds time tag bytes to each MIDI datum within each accumulator period, groups the accumulator periods into data paths. It is further an object that for a given vocalist the transmitter processor deletes any MIDI vocal xe2x80x9cnote-offxe2x80x9d command which is immediately followed by a MIDI vocal xe2x80x9cnote-onxe2x80x9d command. It is an object of this invention that the transmitter processor passes the data to the data combiner processor. It is also an object of this invention that a data combiner processor adds error detection and correction data, and labels the accumulator period to identify the beginning and end of the accumulator periods and to identify which data path each accumulator period belongs.
It is an object of this invention that the data is divided up into accumulator periods at the transmitter. It is further an object that an accumulator period lasts 64/60 seconds in duration. It is another object of this invention that an accumulator period contains 64 data fields which are joined together to form a packet of data. It is another object of the invention that data is labeled with a time tag byte at the transmitter which identifies the time within each accumulator period the data occurs within an accumulator period.
It is an object of this invention that, at the transmitter, error correction and detection data is added to the data, time tag bytes are added to the data, and the data is divided into accumulator periods.
It is an object of this invention for the receiver to have a tuner which can determine if MIDI data is present and isolate that MIDI data. It is also an object of the invention for the receiver to have a receiver processor that detects and corrects errors in the MIDI data and then sends the MIDI data to a sound generator or to a command translator which modifies the MIDI data for usage by an external sound generator which in turn passes the MIDI data to an interface connector for output to an external sound generator. It is an object of this invention that the internal sound generator and external sound generator utilize any available technique such as synthesizer techniques and/or sampled waveforms stored in memory to generate the sounds.
It is another object of this invention that if errors occur in the MIDI data, the receiver processor can detect the errors and either correct the incoming MIDI data or output default MIDI data to ensure proper control of a sound generator.
It is further an object of this invention that the receiver has anti-ciphering logic to mitigate the effects of lost MIDI data by inserting new MIDI data to ensure proper control and operation of the sound generator. Because about one-half of all MIDI data is error detection and error correction data, this invention is extremely robust, permitting the accurate production of sound even under poor broadcasting conditions.
It is an object of the invention that the receiver processor utilizes the time tag byte to place the MIDI data into its correct relative time position within each accumulator period. It is an object of the invention that time tag bytes are utilized to place the data into its correct relative position within each accumulator period by the receiver.
It is an object of this invention that the MIDI data is grouped into a plurality of data paths or data streams. It is further an object of this invention that one data path can contain a sound track distinct from the sound track carried on another data path. In such a manner, one data path may contain the instrumental music for a song, a second data path may contain the lead vocal part in one language, a third data path may contain the backup vocals in the same language, a fourth data path can contain the lead vocal part in a different language, and the fifth data path contain the backup vocals in that second language. It is also an object of the invention that the listener can select, using a user control, which data paths the listener wants to hear. The user control may include a visual display or use the receiver""s display for providing instructions and information to the user. It is further an object to permit the receiver processor to pass the MIDI data in the chosen data paths to the sound generator which emits the sounds. Thus, this invention makes possible the conventional English language transmission of a program with MIDI data conveying the vocals in two other languages (French and Spanish, for example). In other words, this invention permits the conveyance of second and third languages for the same program or song because the data rates are low.
It is an object of this invention that the receiver processor utilizes the packet header to determine to which data path each accumulator period belongs. It is an object of this invention that at the receiver the packet header is utilized to determine the beginning and end of each accumulator period and to determine which data path each accumulator period belongs.
It is an object of this invention that the receiver processor, under user control, can censor vocal sounds or words by selectively blocking specific words, phrases, or sounds which the listener desires to refrain from being heard or played. It is further an object that the receiver processor compares the received MIDI data encoding for words with those MIDI data encoding for words deemed to be undesirable and inhibiting the output of those MIDI data or substituting the undesirable MIDI data with other MIDI data encoding for acceptable words. It is also an object of this invention that selected words, sounds, or other noises can be selectively blocked at the receiver from being generated by the sound generator. It is also an object of this invention that words and sounds can be substituted at the receiver for selected words and sounds by substituting the data encoding for the new words and sound for the selected words and sounds.
It is also an object of this invention that the receiver processor, under user control, can adjust selectively the sound level of the data paths containing voice signals and even adjust selectively the level of certain phonemes for enhanced clarity of speech and also do the same for the vocal parts within a song. This feature may be particularly beneficial to persons with hearing impairments. It is an object of the invention that the receiver processor alters the velocity byte of the selected MIDI data to adjust the sound level. It is also an object of this invention that the velocity byte for selected sounds or words can be adjusted at the receiver, thereby adjusting the loudness of the generated sounds encoded by the data.
It is also another object of this invention that the bit error rate can be determined at the receiver. It is also an object that the average note length for each data path and MIDI channel can be determined at the receiver. Further, the receiver can compare the bit error rate to pre-determined values. It is an object of this invention that when the bit error rate reaches certain pre-determined values, specific MIDI data commands can be suppressed at the receiver. It is a further object that other MIDI commands can be substituted for the suppressed MIDI commands. It is also an object that a time delay is determined and that the time delay can be based upon the value of the received data error rate. It is a further object that when the time delay expires, specific MIDI commands are generated at the receiver. It is further an object that the time delay can be a function of the instrumental music note length, vocal music note length, and/or duration of elementary speech sounds for each data path or MIDI channel.
It is an object of this invention to have a receiver capable of receiving transmitted data which encodes for commands for the generation of sound by a sound generator. It is an object of the invention that the receiver have a tuner capable of detecting the data and a receiver processor for the processing of the data. It is a further object that the receiver have a user control and a receiver clock. It is also an object that the receiver have an internal sound generator and/or be able to be connected to an external sound generator via a command translator and an interface connector. It is a further object that the sound generators utilize any available technique such as synthesizer techniques and/or sampled waveforms to generate the sounds encoded in the received data.
It is an object of this invention that the receiver selectively adds for a given vocalist, new MIDI vocal xe2x80x9cnote-offxe2x80x9d commands immediately preceding MIDI vocal xe2x80x9cnote-onxe2x80x9d commands prior to sending the MIDI data to a sound generator. It is also an object of this invention that at the receiver vocal xe2x80x9cnote-offxe2x80x9d commands are added immediately before vocal xe2x80x9cnote-onxe2x80x9d commands prior to sending the data to a sound generator.